LET’S TAKE AS AN EX­AM­PLE THE BMW Z4 M Coupe of 2006-2009. Con­ceiv­ably, the quoted weight of the lit­tle coupe could vary by as much as 150kg de­pend­ing on which stan­dard it is mea­sured against.

The kerb weight that we like to quote here at evo is the the DIN fig­ure – that’s Deutsches In­sti­tut für Nor­mung, or Ger­man In­sti­tute for Stan­dard­i­s­a­tion. This is the weight of the car with all the flu­ids nec­es­sary for op­er­a­tion, in­clud­ing a 90 per cent full tank of fuel. For the Z4 M Coupe this is 1420kg.

BMW also quotes an EU kerb weight (some­times called EEC kerb weight) of 1495kg. This is the DIN fig­ure plus an ex­tra 75kg for ‘driver and lug­gage’, and is the weight de­clared for emis­sions test­ing.

There is also a ‘dry weight’, which has no stan­dard and is open to a num­ber of in­ter­pre­ta­tions. The most straight­for­ward is the car with an empty fuel tank (as some­times quoted by Lo­tus), but there is also a ‘ship­ping’ dry weight, his­tor­i­cally used by some race car man­u­fac­tur­ers and Ital­ian sports car mak­ers. This means no flu­ids what­so­ever – no oil in the en­gine/ gear­box/dif­fer­en­tial, no coolant, no air con re­frig­er­ant, no bat­tery acid – and also no tool­kit, spare wheel, hand­book, etc.

Quot­ing a dry weight can there­fore make a car’s weight, and by ex­ten­sion its pow­erto-weight fig­ure, ap­pear far more favourable than those of ri­val cars us­ing DIN or EU fig­ures. This is why we mark dry weights in the Knowl­edge with an as­ter­isk.

A sep­a­rate is­sue is Gross Ve­hi­cle Weight (GVW). This is the max­i­mum the ve­hi­cle can weigh on the road when loaded with pas­sen­gers and cargo.

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